%/**
%Focus-vector computation
%@param alpha - elevation, scalar, rad
%@param beta - azimuth, scalar, rad
%@return H - focus-vector
% relevant to antenna's center, 4x1, rad
%*/
function Hv = H( alpha, beta )
k = [cos(alpha)*cos(beta); cos(alpha)*sin(beta); sin(alpha)];
r{1} = [1/4 -1/4 0];
% Antenna's radius-vector, lambdas
r{2} = [-1/4 -1/4 0];
r{3} = [-1/4 1/4 0];
r{4} = [1/4 1/4 0];
phi = nan(4,1);
for i = 1:4
phi(i) = 2*pi * r{i} * k;
end
Hv = exp( 1i * phi );
end